In Tableau, the choice between using an extract and a live connection depends on various factors such as data size, performance requirements, and data freshness needs. Here are the key differences between using an extract and a live connection:

Extract Connection

Definition: An extract is a snapshot of data that Tableau pulls from the source and stores in a highly optimized, compressed format.

Advantages:

1. Performance: Extracts generally offer better performance because the data is pre-aggregated and optimized for fast querying.
2. Offline Access: Since the data is stored locally, you can work offline without needing a continuous connection to the data source.
3. Speed: Extracts can speed up dashboards and visualizations, especially when working with large datasets.
4. Customization: You can create filters and calculated fields in the extract, reducing the need to process these on the fly during analysis.

Disadvantages:

1. Data Freshness: Extracts need to be refreshed to capture the latest data from the source, which might not be suitable for scenarios requiring real-time data.
2. Storage: Extracts require local storage space, which can be a limitation if dealing with very large datasets.

Live Connection

Definition: A live connection directly connects to the data source and queries the data in real-time.

Advantages:

1. Real-Time Data: Provides access to the most current data, making it ideal for scenarios where data freshness is crucial.
2. No Local Storage Needed: Since data is not stored locally, there’s no need to worry about storage limitations.
3. Simplicity: There’s no need to manage extract refresh schedules or handle extract files.

Disadvantages:

1. Performance: Performance can be slower compared to extracts, especially if the data source is large or the queries are complex.
2. Dependency on Source Availability: Requires a stable and fast connection to the data source. If the source is down or slow, it affects Tableau’s performance.
3. Resource Intensive: Puts more load on the data source, which could impact its performance if multiple users are querying it simultaneously.

Choosing Between Extract and Live Connection

Use Extract when:

– You need better performance for large datasets.
– You want to work offline or have limited or unreliable connectivity to the data source.
– You don’t need real-time data and can work with scheduled refreshes.

Use Live Connection when:

– Real-time or near real-time data is critical for your analysis.
– You have a robust and reliable connection to the data source.
– The data volume is manageable, and the data source can handle real-time queries efficiently.

By considering these factors, you can decide the most appropriate connection type for your Tableau project.